you must go to the tower before you go to the hangar. always.
semp
So? As I indicated, the tower has ords status info in the current game version.
But, if you select a plane in the hangar in order to view it's load out - and it has ordnance already equipped - you get a pop up.
It doesn't matter if you know the ords are down or not. Just looking at the plane causes the pop up. You can't remove the ords without first looking at the plane.
I went to the hangar at a base without ords and simply took a look at all the bombers:
If you select a fighter/attack plane, knowing ords are down, you will still get the popup if it has ords on it.